Model predictive control-based optimal voltage regulation of active distribution networks with OLTC and reactive power capability of PV inverters

Abstract

This study presents a model predictive control (MPC)-based centralised control approach for maintaining the voltagesof the nodes within permissible limits in the presence of high photovoltaic (PV) penetration. The proposed control schemecoordinates the actions of on-load tap changer (OLTC) and PV inverters optimally to fulfil the desired objectives. The objectivesare minimisation of change in control variables, slack variables, energy loss, and voltage error. These objectives are weighted toform the overall objective function. Three rules are formulated based on the severity of voltage magnitudes. The weights of theobjectives are adjusted according to these pre-defined rules. Simulations are performed in an active distribution network (ADN)integrated with and without microgrids, where both demands and generations vary hourly over the day. As power is injected bythe microgrids during most of the time of the day, the excursions of node voltages are slightly higher in the microgrids integratedADN. Moreover, the incorporation of the proposed rule-based MPC drastically reduces the energy loss due to active power lossin distribution networks, as is evident from the simulation results obtained by comparing the proposed approach with an existingMPC-based approach.